Earth-boring tools are used to form boreholes (e.g., wellbores) in subterranean formations. Such earth-boring tools may include drill bits, reamers, mills, etc. A conventional fixed-cutter earth-boring rotary drill bit includes a bit body having generally radially projecting and longitudinally extending blades. A plurality of cutting elements may be fixed (e.g., brazed) within pockets formed in the blades. During drilling operations, the drill bit is positioned at the bottom of a well borehole and rotated, and the cutting elements engage and degrade the formation material by mechanisms such as shearing, abrading, etc.
The bit body may comprise materials such as metal alloys (e.g., steel) or particle-matrix composite materials, e.g., cemented tungsten carbide particles dispersed in a metal alloy matrix (e.g., bronze). The bit body may be manufactured by machining, e.g., by milling a steel blank to shape, or casting, e.g., by forming a mold with a negative shape of the desired bit body and filling the mold with molten alloy. Conventionally, the pockets into which the cutting elements are to be affixed are formed in the bit body when the bit body is initially machined or cast to shape. Cutting elements are then affixed within the cutting element pockets using, for example, a brazing process. Other downhole tools also include such cutting elements affixed within cutting element pockets.
Frequently, high-wear areas of steel and other bodies of drill bits and other downhole tools are coated with an abrasion-resistant hardfacing material to reduce wear. Such hardfacing material may comprise particles of cemented tungsten carbide dispersed within a metal matrix material. Hardfacing materials may be applied by welding processes, e.g., plasma-transferred arc welding, oxygen-acetylene welding, gas metal arc welding, or other deposition processes that cause heating of the tool body. The tool body may also undergo thermal processing steps such as heat treatment prior to use of the earth-boring tool in a downhole environment.